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# Copyright (C) 2015 Yahoo! Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
try:
import pydot
PYDOT_AVAILABLE = True
except ImportError:
PYDOT_AVAILABLE = False
def convert(machine, graph_name,
graph_attrs=None, node_attrs_cb=None, edge_attrs_cb=None,
add_start_state=True, name_translations=None):
"""Translates the state machine into a pydot graph.
:param machine: state machine to convert
:type machine: FiniteMachine
:param graph_name: name of the graph to be created
:type graph_name: string
:param graph_attrs: any initial graph attributes to set
(see http://www.graphviz.org/doc/info/attrs.html for
what these can be)
:type graph_attrs: dict
:param node_attrs_cb: a callback that takes one argument ``state``
and is expected to return a dict of node attributes
(see http://www.graphviz.org/doc/info/attrs.html for
what these can be)
:type node_attrs_cb: callback
:param edge_attrs_cb: a callback that takes three arguments ``start_state,
event, end_state`` and is expected to return a dict
of edge attributes (see
http://www.graphviz.org/doc/info/attrs.html for
what these can be)
:type edge_attrs_cb: callback
:param add_start_state: when enabled this creates a *private* start state
with the name ``__start__`` that will be a point
node that will have a dotted edge to the
``default_start_state`` that your machine may have
defined (if your machine has no actively defined
``default_start_state`` then this does nothing,
even if enabled)
:type add_start_state: bool
:param name_translations: a dict that provides alternative ``state``
string names for each state
:type name_translations: dict
"""
if not PYDOT_AVAILABLE:
raise RuntimeError("pydot (or pydot2 or equivalent) is required"
" to convert a state machine into a pydot"
" graph")
if not name_translations:
name_translations = {}
graph_kwargs = {
'rankdir': 'LR',
'nodesep': '0.25',
'overlap': 'false',
'ranksep': '0.5',
'size': "11x8.5",
'splines': 'true',
'ordering': 'in',
}
if graph_attrs is not None:
graph_kwargs.update(graph_attrs)
graph_kwargs['graph_name'] = graph_name
g = pydot.Dot(**graph_kwargs)
node_attrs = {
'fontsize': '11',
}
nodes = {}
for (start_state, event, end_state) in machine:
if start_state not in nodes:
start_node_attrs = node_attrs.copy()
if node_attrs_cb is not None:
start_node_attrs.update(node_attrs_cb(start_state))
pretty_start_state = name_translations.get(start_state,
start_state)
nodes[start_state] = pydot.Node(pretty_start_state,
**start_node_attrs)
g.add_node(nodes[start_state])
if end_state not in nodes:
end_node_attrs = node_attrs.copy()
if node_attrs_cb is not None:
end_node_attrs.update(node_attrs_cb(end_state))
pretty_end_state = name_translations.get(end_state, end_state)
nodes[end_state] = pydot.Node(pretty_end_state, **end_node_attrs)
g.add_node(nodes[end_state])
edge_attrs = {}
if edge_attrs_cb is not None:
edge_attrs.update(edge_attrs_cb(start_state, event, end_state))
g.add_edge(pydot.Edge(nodes[start_state], nodes[end_state],
**edge_attrs))
if add_start_state and machine.default_start_state:
start = pydot.Node("__start__", shape="point", width="0.1",
xlabel='start', fontcolor='green', **node_attrs)
g.add_node(start)
g.add_edge(pydot.Edge(start, nodes[machine.default_start_state],
style='dotted'))
return g
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